I have pain in the middle of my right under arm for two days and now its in my chest above my right boob when i take a deep breath it hurts?

Lymph: Since it hurts on deep inspiration, right apical pleurisy is likely. Pain in armpit could also be from an infection of the lymph nodes going to the chest via lymphatics. If pain is your only symptom, it is hard to be sure.

Muscle: Most pain that increases and decreases with breathing is generally coming from the chest wall. There are muscles between the ribs that take time to heal, intercostal muscles. They have a lot ot of associated connective tissue, thus will take time to recover. You likely made the arm sore at the same time but coughing or unusual movement can cause this. Take 2 aleve (naproxen) twice a day, i may be wrong.

Pleurisy: Pleurisy if inflammation if the inside liing of where the lungs meet the chest wall. Dr kumar is correct, this could be pleurisy. This would be associated generally with an illness. If you have fever get in to see your doctor.